THBS2 and infection: Whereas knockout mutation of Ov-grn-1 did not prevent development and survival of the liver fluke in vivo, infection with these ΔOv-grn-1 flukes failed to lead to marked cell proliferation and fibrosis in the immediate vicinity of the parasites, and consequently fewer hamsters developed high-grade CCA compared with hamsters infected with control and ΔOv-tsp-2 parasites.